rishi/scryer-prolog
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add provisions for arithmetic support.

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This commit is contained in:
Mark Thom
2017-11-05 17:12:30 -07:00
parent a70c100e0d
commit 5568d0b370
15 changed files with 792 additions and 118 deletions
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173
src/prolog/machine.rs
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@@ -4,7 +4,10 @@ use prolog::codegen::*;
use prolog::copier::*;
use prolog::heapview::*;
use prolog::and_stack::*;
use prolog::num::Zero;
use prolog::num::bigint::BigInt;
use prolog::or_stack::*;
use prolog::ordered_float::OrderedFloat;
use prolog::fixtures::*;
use std::collections::HashMap;
@@ -36,7 +39,8 @@ struct MachineState {
tr: usize,
hb: usize,
block: usize, // an offset into the OR stack.
ball: (usize, Heap) // heap boundary, and a term copy
ball: (usize, Heap), // heap boundary, and a term copy
interms: Vec<Number> // intermediate numbers.
}
struct DuplicateTerm<'a> {
@@ -225,9 +229,7 @@ impl Machine {
{
match self.code_dir.get(&(name.clone(), arity)) {
Some(&(PredicateKeyType::BuiltIn, _)) =>
return EvalSession::EntryFailure(format!("error: cannot replace built-in predicate {}/{}",
name,
arity)),
return EvalSession::ImpermissibleEntry(format!("{}/{}", name, arity)),
_ => {}
};
@@ -246,7 +248,7 @@ impl Machine {
self.code.append(&mut code);
self.add_user_code(name, arity, p)
} else {
EvalSession::EntryFailure(format!("error: the fact has no name."))
EvalSession::NamelessEntry
}
}
@@ -261,7 +263,7 @@ impl Machine {
self.code.append(&mut code);
self.add_user_code(name, arity, p)
} else {
EvalSession::EntryFailure(format!("error: the rule has no name."))
EvalSession::NamelessEntry
}
}
@@ -297,6 +299,8 @@ impl Machine {
};
match instr {
&Line::Arithmetic(ref arith_instr) =>
self.ms.execute_arith_instr(arith_instr),
&Line::BuiltIn(ref built_in_instr) =>
self.ms.execute_built_in_instr(&self.code_dir, built_in_instr),
&Line::Choice(ref choice_instr) =>
@@ -408,11 +412,11 @@ impl Machine {
while self.ms.p < end_ptr {
if let CodePtr::TopLevel(mut cn, p) = self.ms.p {
match &self[CodePtr::TopLevel(cn, p)] {
match &self[CodePtr::TopLevel(cn, p)] {
&Line::Control(ref ctrl_instr) if ctrl_instr.is_jump_instr() => {
self.record_var_places(cn, alloc_locs, heap_locs);
cn += 1;
},
},
_ => {}
}
@@ -422,10 +426,10 @@ impl Machine {
self.query_stepper();
match self.ms.p {
CodePtr::TopLevel(_, p) if p > 0 => {},
CodePtr::TopLevel(_, p) if p > 0 => {},
_ => break
};
}
}
}
fn fail<'a>(&mut self) -> EvalSession<'a>
@@ -443,21 +447,16 @@ impl Machine {
pub fn submit_decl<'a>(&mut self, decl: &Declaration) -> EvalSession<'a> {
match decl {
&Declaration::Op(prec, spec, ref name) => {
lazy_static! {
static ref ERR_STRING: String = String::from("an operator can't be both \
infix and postfix.");
}
if is_infix!(spec) {
match self.op_dir.get(&(name.clone(), Fixity::Post)) {
Some(_) => return EvalSession::EntryFailure(ERR_STRING.clone()),
Some(_) => return EvalSession::OpIsInfixAndPostFix,
_ => {}
};
}
if is_postfix!(spec) {
match self.op_dir.get(&(name.clone(), Fixity::In)) {
Some(_) => return EvalSession::EntryFailure(ERR_STRING.clone()),
Some(_) => return EvalSession::OpIsInfixAndPostFix,
_ => {}
};
}
@@ -598,6 +597,18 @@ impl Machine {
}
}
macro_rules! try_or_fail {
($s:ident, $e:expr) => {{
match $e {
Ok(val) => val,
Err(msg) => {
$s.throw_exception(string!(msg));
return;
}
}
}}
}
impl MachineState {
fn new() -> MachineState {
MachineState { h: 0,
@@ -618,7 +629,8 @@ impl MachineState {
tr: 0,
hb: 0,
block: 0,
ball: (0, Vec::new())
ball: (0, Vec::new()),
interms: vec![Number::Float(OrderedFloat(0f64)); 256],
}
}
@@ -753,7 +765,7 @@ impl MachineState {
Ref::HeapCell(r) =>
self.heap[r] = HeapCellValue::Ref(Ref::HeapCell(r)),
Ref::StackCell(fr, sc) =>
self.and_stack[fr][sc] = Addr::StackCell(fr, sc)
self.and_stack[fr][sc] = Addr::StackCell(fr, sc)
}
}
}
@@ -821,6 +833,92 @@ impl MachineState {
};
}
fn get_number(&self, at: &ArithmeticTerm) -> Result<Number, &'static str> {
match at {
&ArithmeticTerm::Reg(r) => {
let addr = self[r].clone();
let item = self.deref(addr);
match item {
Addr::Con(Constant::Integer(bi)) =>
Ok(Number::Integer(bi)),
Addr::Con(Constant::Float(fl)) =>
Ok(Number::Float(fl)),
_ =>
Err("is/2: variable not instantiated to number.")
}
},
&ArithmeticTerm::Interm(i) => Ok(self.interms[i].clone()),
&ArithmeticTerm::Float(fl) => Ok(Number::Float(fl)),
&ArithmeticTerm::Integer(ref bi) => Ok(Number::Integer(bi.clone()))
}
}
fn assign_arith(&mut self, t: ArithEvalPlace, n: Number) {
match t {
ArithEvalPlace::Reg(r) =>
self[r] = Addr::Con(Constant::from(n)),
ArithEvalPlace::Interm(i) =>
self.interms[i] = n
}
}
fn execute_arith_instr(&mut self, instr: &ArithmeticInstruction) {
match instr {
&ArithmeticInstruction::Add(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.assign_arith(t, n1 + n2);
self.p += 1;
},
&ArithmeticInstruction::Sub(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.assign_arith(t, n1 - n2);
self.p += 1;
},
&ArithmeticInstruction::Mul(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
self.assign_arith(t, n1 * n2);
self.p += 1;
},
&ArithmeticInstruction::IDiv(ref a1, ref a2, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
let n2 = try_or_fail!(self, self.get_number(a2));
match (n1, n2) {
(Number::Integer(n1), Number::Integer(n2)) => {
if n2 == BigInt::zero() {
self.throw_exception(functor!("evaluation_error",
1,
[atom!("zero_divisor")]));
return;
}
self.assign_arith(t, Number::Integer(n1 / n2));
self.p += 1;
},
_ => {
self.throw_exception(functor!("evaluation_error",
1,
[atom!("expected_integer_args")]));
return;
}
}
},
&ArithmeticInstruction::Neg(ref a1, t) => {
let n1 = try_or_fail!(self, self.get_number(a1));
self.assign_arith(t, - n1);
self.p += 1;
}
};
}
fn execute_fact_instr(&mut self, instr: &FactInstruction) {
match instr {
&FactInstruction::GetConstant(_, ref c, reg) => {
@@ -1306,13 +1404,6 @@ impl MachineState {
self.write_constant_to_var(addr, &c);
self.p += 1;
},
&BuiltInInstruction::Unify => {
let a1 = self[temp_v!(1)].clone();
let a2 = self[temp_v!(2)].clone();
self.unify(a1, a2);
self.p += 1;
},
&BuiltInInstruction::EraseBall => {
self.ball.0 = 0;
self.ball.1.truncate(0);
@@ -1414,16 +1505,26 @@ impl MachineState {
},
&BuiltInInstruction::Succeed => {
self.p += 1;
},
&BuiltInInstruction::Unify => {
self.inline_unify();
self.p += 1;
}
};
}
fn inline_unify(&mut self) {
let a1 = self[temp_v!(1)].clone();
let a2 = self[temp_v!(2)].clone();
self.unify(a1, a2);
}
fn execute_ctrl_instr(&mut self, code_dir: &CodeDir, instr: &ControlInstruction)
{
match instr {
&ControlInstruction::Allocate(num_cells) => {
&ControlInstruction::Allocate(num_cells) => {
let num_frames = self.num_frames();
self.and_stack.push(num_frames + 1, self.e, self.cp, num_cells);
self.e = self.and_stack.len() - 1;
@@ -1473,7 +1574,15 @@ impl MachineState {
},
&ControlInstruction::ThrowExecute => {
self.goto_throw();
}
},
&ControlInstruction::UnifyCall => {
self.inline_unify();
self.p += 1;
},
&ControlInstruction::UnifyExecute => {
self.inline_unify();
self.p = self.cp;
}
};
}
@@ -1512,7 +1621,7 @@ impl MachineState {
self.registers[i] = self.or_stack[b][i].clone();
}
self.e = self.or_stack[b].e;
self.e = self.or_stack[b].e;
self.cp = self.or_stack[b].cp;
self.or_stack[b].bp = self.p + 1;
@@ -1559,7 +1668,7 @@ impl MachineState {
self.hb = self.h;
self.p += l;
}
},
};
}
@@ -1598,7 +1707,7 @@ impl MachineState {
self.registers[i] = self.or_stack[b][i].clone();
}
self.e = self.or_stack[b].e;
self.e = self.or_stack[b].e;
self.cp = self.or_stack[b].cp;
self.or_stack[b].bp = self.p + offset;